Re: [PATCH] USB: ftdi_sio: Remove tty->low_latency.

From: Greg KH
Date: Fri Oct 02 2009 - 13:02:15 EST


On Fri, Oct 02, 2009 at 10:47:55AM +0200, Johan Hovold wrote:
> On Thu, Oct 01, 2009 at 07:52:21PM -0700, Eric W. Biederman wrote:
> > Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> writes:
> >
> > >> As it stands today ftdi_sio does indeed call tty_flip_buffer_push from
> > >> interrupt context with low_latency set and that is obviously incorrect,
> > >> right?
> > >
> > > It seems to do it from a work queue - or did I miss a case ?
> >
> > ftdi_sio crash quite regularly for me with 2.6.31.
> >
> > With a bunch of nasties like:
> > BUG: scheduling while atomic: swapper/0/0x00010000
> > bad: scheduling from the idle thread!
>
> It's the same problem.
>
> Greg, can't we apply the patch for stable at least? Then we can massage
> ftdi_sio into actually using the work queue for doing _all_ processing
> in the meantime if deemed necessary.

Patches need to be in Linus's tree first, before they can get into the
-stable releases.

I'm still digging through my patch queue, sorry, been swamped with the
-stable stuff, due to the merge window and 4 conferences over the past 2
weeks...

thanks,

greg k-h
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